Image and data security is a major challenge in Storage and Transmission applications. Encryption algorithms for these applications are exposed to various threats and security breaches due to the availability of immensely powerful and inexpensive computational resources. Brute Force and Statistical attacks on the existing cryptographic algorithms is not only possible, but are becoming more practical in the wake of technological advancements like Distributed and Grid Computing. Vast amounts of data can be processed in parallel by agents distributed over the Internet and aid in revealing secure information. Several data encryption algorithms like DES [1], AES[1], IDEA[1] are being employed for protecting digital information, chaos based [5][17], combinatorial permutation [13] and optical techniques [12] are also proposed for encrypting images. Along with these developments in the security domain, the vulnerability of the algorithms are also being exposed. It is possible to build a machine that can determine the key used for DES encryption at a cost as low as US $10000 [16]. It is also vulnerable to Linear and Differential cryptanalysis or a combination of both. Techniques like the Side Channel Attack and several Cache Timing Attacks have been developed to compromise AES algorithm and retrieve the encryption key in as less as 65 ms with 800 write operations [6]. Chaos based techniques like the CKBA are prone to plaintext attacks [7] and algorithms using combinatorial permutations are as strong as the permutation of the least sized block even if they apply multiple permutations over different sized image blocks.
Applications in the Automobile, Medical, Construction and the Fashion industry require designs, scanned data, building plans and blue-prints to be safe-guarded against espionage. Considering the long lifetime of images in the mentioned domains, it is imperative to develop and employ techniques which protect the content throughout their lifetime.
It is an object of the present invention to address one or more of the above problems. In particular, an object of the invention is to provide techniques for protecting the content of digital images.